Run up the path to find Brienna Starglow locked in combat with Rau Cliffrunner. She offers Save the Sentinel, so pick it up before heading out. Cross the first two bridges, then circle around back to the east to head to Freewind's upper level to save the sentinel. Jump down to the water and head back to the southeast to avoid some fighting if desired. Brienna offers the follow-up, Together Again.